Obobg gtbabe



G. GRABE.

TELEPHONE SYSTEM.

APPLICATION msn MAR,23.1915. nENEwED AUG. 2|, 191s.

Patented May 13, 1919.

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@my Gru@ y sTATEs `'PA'.rEncrf oEEioE:

To all whom t may concern.'

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@none omis, or miconassnii, NEAR, iaEnLiNfeEnMANY,

Ensim 5.4i., or annum, GERMANY, 'A coaroiwrio'iror annum.

'.rELErHoNE SYSTEM.

spammen of Enterrement.

` 1915,.Ser1a1 18,424. `Renewed August 21, 1918. BerlalNo. 250,893.

Be it known that I, GEORG Queen, a German citizen, and resident of Nikolassee, near Berlin, Germany, have invented certam-new and useful Improvements in Telephone. Sys.

tems, of which the following is a specification.

This invention relates totelephone systems, the present application .being av division of my application Ser. No.v 795,285 iiled ctober15 1913. v

ln telephone systems having numerous lines originating calls such as subscribers ,lines 'or trunk lines it is known to connect said lineswith trunk lines less numerous tn -said lines by means of switches known `as call seekers associated with said trunk lines'. Since the number of lines to be tested by a call seeker isusually very `large it is necessary that the call seeker run with a high speed, y

` he `bject fof my invention is to increase the speed of such call seekers by having the adjusting member retained at a desired contact by means of a locking meehanismwhich.

ismechanically brought into locking position and retained therein b a change4 of the magnetic condition of t e test electroma et.

y invention will be' more fully understood byv reference to thel accompanying drawings, in whichl y Figure 14 hows a selectorat its zero o.- sition in form of a call seeker, rovi ed with an arrangement according to t einvention.

Fig. 2 is .a diagram showing the connections for the selector according to Fig. .1.

Referring to Fig. 1, on the'shat 1- of 'al' call seeker provided with contact arms en d a series of xed contacts (not shown) is keyed va pulley 2 which is operated by a cord` 16. On the shaft 1 is also mounted 'a ratchet. wheel 6 having'a'n escapement in thefor'm of a pawl. 7. Said pawl is provided with an extension 8 formmg the armature of a test 1 relay P. This extension 8 isretained in its 7 is preven normal position by means ofthe noseli of the bell crank lever 9 having its ulcrum at 10, said lever 9 being arran ed adjacent he cord 16 ulley 2 as long) as the 4pawl from moving y lthe detent slides on the will, however, be su ground,- whereb selector illustrated is a call seeker having no particular zero-position, the selector will remain upon the contact to which it has been adylusted after the connection, has been broken. he `selector is provided with a* peculiar arrangementin order-to prevent starting if it is in a position to engage a free connecting line. Therefore, the test relay must be excitedfbefore starting the selector, so that in the call-relay R the awl 7 will yet remain in its locked position. he construction of relay R is such that it may close by its contact r the 'circuit forenergizing the relay P, withoutl attracting its armature 9 for releasing the locking member 7 until after a sufliciently strong energization of the relay P, so that the pole-stren h of the relay P will be suiiicient to retain t efpawl 7 in its locking position. For this purpose thecore g of the relay R is mounted in-a frame 19 of nonmagnetizable material so that upon. the relay R becoming excited the magnetic circuit at either assienon ro siemens a i v I r V Patented May 13, 1919. original. ap'pniuoa tieioutber is', isis, semi in. 795,255. inviamil una inisappueauen nieu umh ae,-

spite of the escapement 7 being released by pole will still. be cpen. The energization cient for attracting the armature 20 and closing thecontact r. By the armature 20 the yoke re uired for closing the magnetic circuit'will i e formed and the field strength of the relay 'R will'thereb be increased tosuch an extent that it wi 1 yattract .the leverannature 9 for releasing the projection 8 against vthe action of the spring 11 -whereb the escapement 7 is also released.

1`he mo e of operationof the connections shown inFig. 2 for a callseeker according to` this invention 'is now as follows: If the subscriber X takes oi the receiver a circuit will be closed from ground, back contact t1,

subscriber apparatus X,back contact t2,

relay M 'starting relay A the rela s energized. he relay ing. contact m and therewith impresses the testin potential upon the call seeker con' tact In closing the working contact an vby the/call relay An, the call relay R of the free call seeker AS will be excited' over the call `distifibuter WS working in a well known mannensaid call seeker R as men- `battery tol and Aat will closes its worktioned closino' first the contact r. If ,n ow vincidentall tIie call seeker AS is contactin with ya cal ing line A, B, the relay P w11 become excited in a circuit from\ round to battery, working contact m, one winding of the relay T,- contact C, working contact. 7 test relay P, contact a to ground. The field strength of the relay R will then be increased to such an extent, that it will attract its armature. The selector, however,

will not be started since the rela P was al- Iready excited before the relay attracted its armature. Therefore, the relay P holds its armature 8attracted and the escapement 7 remains in the position shown. B closing the working contact t, of the re ay T, whichv was simultaneously excited' in the same circuit with the relay P, the high resistance winding of the relay T is included in the circuit. At the same time the vback contacts t, and t2 are opened so that the relays M and An will become denergized and the starting circuit disconnected.

Therefore, the contact m is opened and thus the resistance in the circuit of the relay T increased' whereby the calling line will be busy in the known manner. By the ener-l gization of the test relay P the working contacts p1, p2, p, will be closed, so that connection isl established to the feeding bridge over relay E. By the energization of the relay E the contact e is closed and the l slow acting relay V excited. The contacts fv and 'v2 are closed and the slow acting) relay W is excited which .will open the ack contact W. In the known manner, after deenergizing of the starting relay An the distributer WS will be adjusted upon the next free call nder and the call finder AS now engaged will be busy for any other call. Disconnecting is done in the known manner by opening the contact z whereby the relays P and T will become ino erative. The selector nowwill not be a le to start again because immediately after dener izing of the relay R the lever 9 will again all down into its locking position and lock'the projection 8 of the escapement 7. y

1. In a telephone system, lines originating calls, trunking apparatus, switches less numerous than said lines to connect said lines with said trunking apparatus, said switches comprising a locking device for -retaining the adjusting member in a contacting position, mechanical means for bringin said locking device into locking position y the moving force for 'said adjusting member,

and magnetic means for immediately operating said locking member when in locking position.

2. In a telephone system, lines originating calls, trunking apparatus,l switches less numerous than said lines to connect said lines with said trunking apparatus, said switcher locking device into lockin comprising a locking device for retaining the adjusting member in a contacting position, mechanical means for bringing said position y the moving force for said a justing member, and ma etic means for immediately operating said lockin member when in o position and at t e moment of contactv between said adjusting member and said callingl line. y ,l f

3. In a telephone system, lines originating calls, trunking apparatus, switches less numerous than said lines to connect said lines with said trunking apparatus, said switches comprising yan adjusting member, a locking device for retaining said adjusting member in a-contacting position, mechanical means for bringing said locking member into locking position by the moving force for said adjusting member, a test magnet for immediately operating said locking member when contacting with a calling line and means for varying the 4magnetic condition of said test magnet. V

4. In a telephone system, lines originating calls, trunking ap aratus, switches less numerous than said with said trunking apparatus, said switches comprising a locking device for retaining the adjusting member in contacting position, mechanical means for bringing said locking device into locking position by the moving force for said adjusting member,

magnetic means for immediately operating ing member is in its nearest position to said,

magnetic means.

5. In a telephone system, lines originating calls, trunking apparatus, switches without zero-position less numerous than said lines to connect said lines with said trunkin apparatus, said switches comprising a loc ing device for retaining the adjusting member in a contacting osition, mechanical means forbringing sai locking device into locking position .by the moving force for said adjusting member, and `magnetic means for immediately operating said locking member when in locking position.

6. In a telephone system, lines originating calls, trunking apparatus, switches without zero-position less numerous than said lines to connect said lines with said trunking apparatus, said switches comprising a locking d evice for retaining the adjustin member in a contacting position, mec anical means for bringing said locking device into lockin position by. the 'moving force for said a justing member, magnetic means for immediately operating said locking member cking nes to connect said lines Lacasse when in locking position, and magnetic means for releasing said locking member.

7 In a telephone system, lines originating calls trunking apparatus, switches Without zero-position less numerous than said lines to connect said lines with said trunking apparatus, said switches comprising a lockl ing device for retaining the adjusting memlber 1n a contacting position, mechanical means for bringing said locking device into lookin@r position .by the moving force for said ajusting member, magnetic means for immediately operating said locking member when in locking position,l magnetic means for releasing said locking member, said magnetic releaslng'means closing a circuit. containing.;r said magnetic means for operating said-locking member before releasing said locking member.

In testimony whereof I have hereunto set my signature m the presence of two subscribing iwitnesses.

` GEORG GRABE. Witnesses:

HENRY HIASPER, WOLDEMAR Hamai'. 

